Fig. 2. Concentration dependences of the onset oxidation temperatures for individual heating rates MH: 6 = 1 Kmin™', O:6=3Kmin|, a: 6=5Kmin', V: 6=7Kmin', @: 6=10Kmin', DC: 6=15Kmin—. From Eq. (3) it is obvious that if the value of PF is greater than one, the additive has a stabilizing effect on he polymer. In Figs. 3—5, the protection factor of PP and recPP stabilized with lignin and/or Irganox 1010 is plotted as a function of temperature. Figs. 3 and 4 show he dependences of PF on temperature for the PP and recPP samples stabilized with various concentrations of ignin. These dependences exhibit increasing tendency with decreasing temperature and with the increasing content of lignin. Dependences of PFs on temperature for the samples stabilized with Irganox 1010 and with he mixture of Irganox 1010 and lignin are depicted in Fig. 5. It is obvious that the stabilization of recPP by Kinetic parameters A, B and their standard deviations Table 2 Fig. 1. Experimental and fitted dependences of the onset oxidation temperatures on the heating rates for polypropylene stabilized with lignin in various concentration. Antioxidant effectiveness Table 3 Fig. 3. Dependences of protection factor on temperature for lignin ir PP. Fig. 4. Dependence of protection factor on temperature for lignin in recPP. Fig. 5. Dependence of PP protection factor on temperature for Irganox 1010 and lignin. VST of PP and recPP stabilized with Irganox 1010 and lignin Table 4 Fig. 6. Dependence of VST on lignin content in PP and recPP.
